1. Field of the Invention
This invention relates in general to a mass storage systems for computer systems, and more particularly to an improved dual actuator pivot bearing system and method for making the same.
2. Description of Related Art
Fixed-magnetic disk systems, typically referred to as “hard” disk drives, are now commonplace as the main non-volatile storage in modern personal computers, workstations, and portable computers. Such hard disk drives are now capable of storing gigabyte quantities of digital data, even when implemented in portable computers of the so-called “notebook” class. Many important advances have been made in recent years that have enabled higher data density and thus larger storage capacities of hard disk drives, and that have also enabled much faster access speeds, both in the bandwidth of data communicated to and from the hard disk drive, and also in the access time of specified disk sectors. Advances have also been made that have greatly reduced the size and weight of hard disk drives, particularly as applied to portable computers, have been made over recent years. These advances have resulted in the widespread availability of ultra-light portable computers, yet having state-of-the art capability and performance.
A head/disk assembly typically comprises one or more commonly driven magnetic disks rotatable about a common spindle and cooperating with at least one head actuator for moving a plurality of heads radially relative to the disks so as to provide for the reading and/or writing of data on selected circular tracks provided on the disks. As track pitch decreases, servo performance will decrease because of the more stringent tracking criteria unless a break is made with current disk drive design. One proposal has been to put two independently controlled actuators on one disk drive. Servo performance is then increased because one actuator can seek to a new location while the second actuator is accessing data. In this way the seek and settle time is hidden from the user: he sees instead only the final portion of the seek that occurs when the data access on the other actuator has completed.
However, prior designs for dual actuator pivots have present several manufacturing problems. One problem with prior dual actuator pivot designs is that they have twice as many sleeves and ball bearings as a standard pivot. Outgassing potential is doubled because ball bearings are adhesively bonded to the shaft and sleeve. In addition, with twice as many adhesive joints the risk is doubled of having an adhesive bond fail with catastrophic results to the file. Yet another problem is the assembly time. Because a dual actuator pivot requires the assembly steps equivalent to two pivots, it naturally take twice as long to assemble.
It can be seen then that there is a need for a dual actuator pivot bearing system and method for making the same, wherein the need for adhesive bonding is eliminated and assembly time is minimized.